1. Field of the Invention
The present invention relates to an electrical connector for electrically connecting an electronic package such as a central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB), and particularly to an electrical connector having a cam actuator with reduced assembly tolerance and enhanced strength.
2. Description of Related Art
An integrated circuit (IC) package having a multiplicity of pins depending from a bottom surface thereof and arranged in a grid array is known as a pin grid array (PGA) package. Connectors for electrically connecting PGA packages with PCBs are known as PGA sockets.
A PGA socket comprises a base having a multiplicity of terminals arranged in a grid array corresponding to the lead pins of the PGA package, a cover defining a multiplicity of through holes arranged in a grid array corresponding to the lead pins of the PGA package, and a cam actuator for actuating the cover to slide along the base. The PGA package is mounted on the cover, with the lead pins received in the through holes. When the cover is slid, the lead pins mate with the terminals.
A conventional electrical connector for high-density pins is disclosed in xe2x80x9cHigh-density PGA Socket Systemxe2x80x9d (April 2000, Electronic Engineering). Such socket connector generally adopts a cam actuator for actuating a cover of the socket to slide along a base of the socket. Typical cam actuator structures are disclosed in U.S. Pat. Nos. 6,250,941, 6,254,415, 6,280,224, 6,296,507, and 6,338,640.
Referring to FIG. 6, a conventional electrical connector 5 disclosed in U.S. Pat. No. 6,338,640 comprises a generally rectangular insulative base 50, a cover 52 slidably attached on the base 50, a multiplicity of conductive terminals 58 received in the base 50, a cam actuator 56 for actuating the cover 52 to slide along the base 50, a protecting mechanism and a base ring 59. The protecting mechanism comprises a base plate 542 secured in the base 50, and a cover plate 541 secured in the cover 52. The cam actuator 56 comprises several short, round columns one on top of the other. Circumferences of the columns sequentially decrease from top to bottom of the cam actuator 56. Central axes of the columns are offset from each other. A topmost column outwardly forms a protrusion in a radial direction.
Referring also to FIG. 7, in assembling the electrical connector 5, the columns of the cam actuator 56 are sequentially passed through the cover 52, the cover plate 541, the base plate 542 and the base 50. The base 50 and the cam actuator 56 cooperatively define a fastening space 501 therebetween. A bottommost column of the cam actuator 56 is disposed in the fastening space 501. The base ring 59 is inserted into the fastening space 501 and riveted to the bottommost column of the cam actuator 56. Thus the base 50, the cover 52, the cam actuator 56 and the protecting mechanism are assembled together.
The overall assembly tolerance of the cam actuator 56 received in the base 50 comprises the manufacturing tolerance of the base plate 542, the manufacturing tolerance of the base 50 and the assembly tolerance between the base plate 542 and the base 50. Thus the overall assembly tolerance of the cam actuator 56 is unduly large.
The unduly large overall assembly tolerance of the cam actuator 56 results in unduly large interspaces existing in the assembled electrical connector 5. The assembled electrical connector 5 is liable to be unstable. In particular, the cam actuator 56 is prone to tilt, and excessively large force may be required to operate the cam actuator 56. Furthermore, the fastening space 501 is relatively small. Accordingly, the bottommost column of the cam actuator 56 received in the fastening space 501 is relatively short. This limits an amount of fastening force that can be applied on the bottommost column when the base ring 59 is riveted thereto. Moreover, the base ring 59 is liable to contact the nearby PCB.
In view of the above, a new electrical connector that overcomes the above-mentioned disadvantages is desired.
Accordingly, an object of the present invention is to provide an electrical connector for electrically connecting a CPU with a PCB, whereby the electrical connector has a cam actuator with reduced assembly tolerance and enhanced stability.
Another object of the present invention is to provide an electrical connector for electrically connecting a CPU with a PCB, whereby the electrical connector has a cam actuator with enhanced strength.
To achieve the above-mentioned object, an electrical connector in accordance with a preferred embodiment of the present invention is for electrically connecting a CPU with a PCB. The connector comprises a generally rectangular insulative base, a cover slidably attached on the base, a multiplicity of conductive terminals received in the base, a columnar cam actuator for actuating the cover to slide along the base, a protecting mechanism, and a base ring. The protecting mechanism comprises a base plate secured in the base, and a cover plate secured in the cover. The base plate comprises a base portion, and a raised portion upwardly formed from a middle of the base portion. The base portion and the raised portion cooperatively define a fastening space therebetween. In assembly of the connector, the cam actuator is sequentially passed through the cover, the cover plate and the base plate, and a bottommost column of the cam actuator is thus received in the fastening space. The base ring is inserted into the fastening space and riveted to the bottommost column of the cam actuator. Thus the base, the cover, the cam actuator and the protecting mechanism are assembled together. The overall assembly tolerance of the cam actuator received in the base is merely the manufacturing tolerance of the base plate. The bottommost column of the cam actuator can be relatively long. This enables a relatively large fastening force to be applied to said column when the base ring is riveted thereto.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: